Few childhood treats scream “summer” like a brightly colored, ice-cold slushie. Whether enjoyed poolside, after sports practice, or as a sweet break on a hot day, these sugary frozen drinks are beloved by kids and adults alike. But behind their cheerful colors and frosty appeal lies a hidden risk—especially for young children.
That risk is glycerol, a food additive used in many slush drinks to keep the ice soft and drinkable. Though it’s approved for food use in both the U.S. and Europe, glycerol can cause serious health issues in children when consumed quickly or in large quantities—often resulting in symptoms that mimic rare metabolic disorders. Recent research is now helping us understand exactly what happens in the body during these episodes—and how to avoid them.
The Hidden Ingredient: What Is Glycerol?
Glycerol (also listed as E422 or glycerin) is commonly used in slushies to prevent them from freezing solid without adding more sugar. It’s considered safe in low doses for adults. However, in children—especially those under age 8—glycerol can build up rapidly in the bloodstream, causing dangerously low blood sugar, disrupted potassium levels, and even seizures.
One study published in Archives of Disease in Childhood documented 21 children in the U.K. and Ireland—most of them toddlers or preschoolers—who became critically ill within an hour of drinking a slushie. These kids were healthy beforehand, and the sudden, dramatic symptoms confused doctors, many of whom initially suspected rare inherited disorders.
A Metabolic Meltdown in a Cup
Here’s what was happening: glycerol, though benign in small doses, overwhelms a child’s system when ingested quickly in a large volume. A 500ml slushie might not seem like much, but for a small child, it’s more than their liver can safely process, especially if they’re hungry or have just exercised.
Normally, the liver converts glycerol into glucose. But when overwhelmed, the process stalls. Blood sugar crashes, and acid builds up in the blood—a condition called metabolic acidosis. Nearly every child in the study showed signs of low consciousness, low potassium, unusual blood fat readings, and some even experienced seizures. Urine tests confirmed the culprit: elevated glycerol levels.
In one striking case, a child who had previously been hospitalized after a slushie had a second reaction three years later—but this time, the parents recognized the symptoms and gave glucose right away. The child recovered before even reaching the ER, confirming the root cause wasn’t a disease, but an avoidable ingredient.
Why Are Children So Vulnerable?
Young kids have smaller livers and immature enzyme systems, making it harder for them to metabolize large amounts of certain substances. On top of that, glycerol draws water across cell membranes, which is helpful in medical settings to reduce brain swelling—but risky when consumed unexpectedly in a drink. This water shift can affect potassium levels and increase intracranial pressure, potentially contributing to drowsiness and seizures.
It’s not just how much glycerol is consumed, but how fast. Downing a slushie in minutes, particularly on an empty stomach or after physical activity, creates the perfect storm for a metabolic crash.
What Parents Can Do to Keep Kids Safe
Slushies may seem innocent, but given the data, it’s clear that for children—especially young ones—they pose a genuine health risk. The good news? There are easy, healthy ways to satisfy those icy cravings without the hidden dangers.
1. Skip the Slushies — Especially “Sugar-Free” Ones
Most of the dangerous cases involved sugar-free or reduced-sugar slush drinks, where glycerol is more heavily used. If you’re unsure what’s in a slushie, assume it contains glycerol unless the label clearly states otherwise. Better yet, avoid them altogether.
2. Serve Whole-Fruit Frozen Treats
Kids love cold, sweet snacks, so swap commercial slushies for blended frozen fruits like watermelon, strawberries, or mango with a splash of coconut water. These treats hydrate and nourish, without disrupting metabolic balance.
3. Make Sure Kids Eat First
Glycerol toxicity is more likely when children are fasting or tired. If your child hasn’t eaten recently, don’t let them consume any sweetened drinks. A small snack like a banana, some nuts, or even a boiled egg beforehand helps create a buffer.
4. Teach the Art of the Slow Sip
Speed matters. Train kids (and model for them) to sip slowly, especially with anything cold or sweet. Taking time gives their body a chance to process ingredients safely.
5. Spread the Word
This isn’t common knowledge. Most caregivers have no idea that slushies could send a child to the emergency room. Share what you’ve learned with grandparents, teachers, babysitters, and friends. A little awareness can prevent a major health scare.
The Bottom Line
Slush drinks are marketed as fun and refreshing—but for small children, they may pose a very real danger. Glycerol might sound harmless, but in the wrong context, it can cause a cascade of metabolic chaos.
By choosing whole foods and fostering healthier treat habits, you’re not just dodging a summer scare—you’re giving your child the gift of balanced energy and long-term wellness.
Because what’s inside your child’s cup matters just as much as what’s on the outside.
Dr. Joseph Mercola is a New York Times bestselling author and health advocate. For more health insights, visit Mercola.com.
This article is reprinted with permission from Spirit of Change Magazine.